Porous GaAs (pi-GaAs) has been fabricated using pulsed current electrochemical etching. Scanning electron microscopy (SEM) shows that the time off (T-off), time on (T-on), and cycle time (T) can promote thicker and more uniform pi-GaAs layers compared to those of direct current etching. Choosing suitable pulse parameters produces pi-GaAs layers with a thickness of 90 mu m and crystallite size of 2.4 nm. X-ray diffraction (XRD) shows a high degree of crystallinity of the samples. Photoluminescence (PL) spectra showed two or three PL bands besides the PL band of the single-crystalline GaAs (c-GaAs). Peak PL wavelengths were located approximately at 362, 426, and 540 nm. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3059005] All rights reserved.